In my application U.S. Pat. No. 524,747 filed Nov. 18, 1974, now U.S. Pat. No. 3,980,024 entitled Air Propelled Vehicle Transportation System there is disclosed a system in which the air used to drive a vehicle through a conduit is nearly totally injected into the conduit at one end through orifices in the conduit wall and nearly totally withdrawn through a second set of orifices formed in the conduit wall adjacent the other end. In my prior application, only a minimal amount of air enters or exits either portal even though both are open at all times and un-gated. The prior system is used where special conditions require that little or no air enter or leave the conduit at both portals.
There are many installations, however, where little or no air can be permitted to enter or exit at the entrance end only. The other end may not require such a special condition and air may exit freely through the other end. Such a situation exits where it is desired to transport objects out of an air conditioned or heated building. In order to prevent loss of the heated or cooled air of the building, it is desirable to move the objects using the air outside the building yet eliminate any movement of air in or out of the building through the conduit.